Sure, this is fan-fic and no, there's no way it's going to happen as it has no grounding in reality. And sure, I'm kind of pulling stuff out of my ass as I'm writing it. But dammit, this is what I would like to see happen in the next installment of Christopher Nolan's take on the Batman franchise.....
*CONTAINS DARK KNIGHT AND BATMAN BEGINS SPOILERS*

Two years after the events of
The Dark Knight, Batman is still on the lam for the crimes perpetrated by the late District Attorney Harvey Dent. Believing that Batman is responsible for Dent's five murders--two of which were cops--members of the Gotham City police force are getting desperate in their manhunt of the Caped Crusader. In a final attempt at catching Batman, investigators have called on
Edward Nygma, a thief who was captured by Batman between the events of
Batman Begins and
The Dark Knight, to assist the police in exchange for a full pardon of his crimes. With his incomparable intellect and rationalizing skills, Nygma can decipher clues and think in abstract ways to find the evidence necessary to lead the police straight to Batman. In other words, he's virtually impossible to out-smart. Besides, who better to think like a criminal than another criminal?
Unlike
previous interpretations of the Riddler, this one would not be a svelte, goofy man wearing garishly green tights covered in question marks. This Riddler is collected and controlled, pristine in appearance, and calculating and unblinking in his every move. He's an obsessive compulsive egoist, both meticulous and mysophobic. To put it succinctly, this Riddler is more like Hannibal Lector than Screwy Squirrel.
While Commissioner Gordon and the rest of the police force have their hands full with the Riddler, Batman carries on as usual, catching crooks and undermining the criminal element in Gotham. Just as Batman has a handle on things, Talia Al Ghul, daughter of the fallen
Ra's Al Ghul from
Batman Begins, comes to Gotham City with the last members of The League of Shadows to exact revenge on the man who killed her father. While she sends her minions to do her bidding and fight Batman, Talia investigates Gotham's high society by posing as a rich CEO to learn more about who could've killed her father. As she mingles with the prestige class of Gotham, she becomes interested in a Mr. Bruce Wayne.
Bruce sees in Talia something that he had never seen in any other woman since the passing of Rachel Dawes. As Bruce and Talia both draw closer to each other--romantically and physically--they begin to question the reason for their alternate lives. Is the past really worth clinging on to if it means losing your potential future? What would happen if you simply stopped fighting? Would anyone notice or care?
Just as Bruce Wayne begins to contemplate hanging up the cape and cowl, The Riddler starts to close in on his investigation. While rummaging through the police files concerning Batman, Nygma discovers that Gordon has been covering for Harvey Dent this whole time, and that Batman is innocent of the murders. Seeing an opportunity for blackmail, Nygma turns the screws on Gordon in order to get leverage. Now that he has the upper hand, The Riddler will stop at nothing to seek revenge on the only person who has ever caught him--Batman.
Will the Riddler get the Gotham Police force under his thumb and amass a platoon of Gotham's best boys in blue to take down the Batman once and for all? Will Bruce Wayne give up being Batman, or will he rise up and fight in his darkest hour? Will Talia discover that Bruce Wayne and Batman are one in the same? Stay tuned! Same bat-time, same bat-channel!
If this were to happen--any of it--the main thing I'd like to see is
Crispin Glover play The Riddler. As far as I'm concerned, there's no one else.
Fuck Johnny Depp. Seriously. Just take Crispin Glover, dress him in a dark green, three piece suit, dye his hair a dark shade of red... presto.
Given Heath Ledger's performance as The Joker, the last thing you want in your sequel is for a very similar, but less interesting, villain. So instead of an extroverted loud-mouth, go for someone quiet and introverted. That's why I want my version of The Riddler and why I want Crispin to play him.
As for Talia, get any pretty, exotic-looking woman (Ra's Al Ghul's reach was global, so her mom could be anyone) who is a decent actor.
Aishwarya Rai, maybe? I don't know. I'd actually rather see a newcomer be given the chance to show up and just wow everybody. Whoever it'd be, it would have to be someone who could go toe to toe with Christian Bale and have some chemistry with him.
Well, that's my thoughts. What are yours? What do you want to see in a sequel?